ERECTION AND MANAGEMENT OF GREENHOUSES. 
21 
the advantage of steaming. The two end flues run under the front 
walk, and me#ing iirthe middle of the house, cross and discharge 
themselves at the two chimnies in the centre of the back wall, and 
the two centre fires pass under the centre walk, and discharge them¬ 
selves at the two end chimnies. 
The walks are three feet six inches wide, and are composed of bars 
of wood four inches broad and an inch and a half thick, nailed half an 
inch apart upon strong hearers. 
The price for erection stands about as follows:—Deal wood, taking 
an average, including the scantling, &c. &c., will scarcely exceed 2id. 
per foot; sawing the same 4s. per hundred feet; workmanship 2id. 
per foot; Glass six inches by three for the roof 6d. per foot; Gla¬ 
zing lid. per foot; pillars 10s. per cwt.; front foundations, and the 
Qiitire fitting up, as flues, &c. &c. entirely depend on local situation 
and other circumstances. And now for a few remarks on the manage¬ 
ment of greenhouse plants. 
Greenhouse Plants should never he supplied with much water in 
wet or frosty weather, and none unless the soil in the pots becomes 
dry. This rule must be particularly attended to, from the beginning 
of November till the end of February. 
•j 
In March, the plants may be occasionally syringed overhead to 
clear and refresh the leaves, but always select fine days for the pur¬ 
pose ; and let this, as well as the general waterings, be done in the 
morning, from the middle of September till the beginning of May, 
and at all other times in the evenings. 
As the season advances, and the weather becomes milder, increase 
the quantity of air, until, by the middle of May, a large portion of 
air maj be left on all night, except in case of severe frost. And 
this rule of admitting air must be attended to throughout the winter 
at every convenient opportunity : but always make a practice of shut¬ 
ting up early in the afternoon. 
Always keep the plants clean, and perfectly free from dead leaves 
and weeds; this must be particularly attended to in the winter sea¬ 
son. 
About the beginning of March repot all the plants that require it, 
and top-dress the remainder with good fresh soil. Some free-grow¬ 
ing kinds may require potting two or three times in the course of 
the summer, but the last potting should never be later than the mid¬ 
dle of September. 
As Greenhouse Plants differ materially from each other in habits, 
so also the soil suitable for them must vary in proportion. For a 
general idea on the subject, the following, (noticed 'Vol. 1, p. 499,) 
